"Do you have a lot of students who are learning guitar in order to accompany their voice?"
And the answer, for me, is definitely, yes. Maybe that's because I pick up a lot of my students through The Woods Music and Dance Camp, where I've taught beginning guitar off and on for years and where the emphasis is definitely on singing-- or the song circle, which is an offshoot of The Woods, and similarly is made up of people interested in singing folk songs. Maybe it's because most people think of me as a singer more than a guitarist. Who knows.
But I've also learned not to take on students who are looking for something I can't offer. I don't play music from a staff, I can't teach someone the ins and outs of rock or heavy metal music. So I don't teach students who are looking for that. I teach people who want to play guitar well enough to accompany themselves singing. And I'm pretty up front that we're going to be working mostly with folk songs. Which is not to say we won't go a little off the path into something by the Eagles, Neil Young, or other stuff like that if that's what they're into.
Where I've sometimes had to push a student is sometimes with teenagers who are shy. So I just do all the singing and let them follow along. I figure when they're ready to sing, they'll sing!